Apparatus for the manufacture of casein



Feb. 13, 1940. 55.05am; 2',l90;136

APPARATUS FOR THE MANUFACTURE OF CASEIN s h In I0 Original Filed ApriL- 29. 1937 [N VENTOR fame 8.052116 .4 T TORNE or several days thereafter putrefaction may set in and attack the unreacted milk which has- Patented Feb. 13, 1940 a APPARATUSFOR THE MANUFAGTUBEO'F CASEIN" Elmer B. Oherg, Evanston, Ill., asslgnor to United States Gypsum Company, Chicago, 111., a corporation of Illinois W Original application April '29, 1937, Serial N 139,767. Dividedand this application September 15, 1937,. Serial No. 163,897 z This invention relates to'the manufactureof an improved type'of casein or other proteins, and

also has reference to a novel apparatus for producing the casein. i

In producing casein by conventional means, the milk is heated to a temperature of approximately -120 F. and then is allowed to. come in contact with dilute solution of a mineral acid, such as hydrochloric or sulfuric acid, which'immediately precipitates the casein in a form of agglutinated masses of casein whichmay contain a'considerable amount of occluded foreign matter and whey. The formed caseintogether with the acid whey is allowed to stand in a tank whereby the casein settles to the bottom and the whey is removed. Additional quantities of water,

either plain or slightly acidulated with theprecipitating acid, are then added to". the tank to wash the precipitated casein curd. The curd is washed by agitating in the plain or acidulated water. This process is repeated several times in.

It should be noted that in many cases,'m'echanical shredding means are used to tear apartthe pressed casein curd preliminary to spreading 1 upon the drying frames. After drying for a pearlod from 6 to 8 hours, the casein emerges from dryingthroughout the caseinparticles, whereas dried casein is then ground to the desired degree 1 of fineness, sacked and placed in storage or the drier with about 10% moisture content. The

shipped to the market.

The major bulk of casein produced should'be very low in ash; Much casein. as produced by the conventional meanshas a higli ash content, 7 and in addition contains occluded impuritiesdiflia cult to remove by washing.

casein curd which are produced immediately upon the addition of the acid to the not only occlude large amounts of the whey but also in some instances even occlude small portions. of the milk which cannot be removed except by prolonged washing. Afterpassage to, the ,drier been occluded in thecasein agglutinateclmasses and give off a very disagreeable odor. Furthermore, the occluded unreacted milk will have a,

to solution by acids "as well as alkalies.

The pressedcasein curd is spread upon drying trays, inserted into a tunnel drier and dried at a temperature about F's-130?, F;

tendency to brown and become scorched during the drying or subsequent grinding" operation. This results in a product which is known in the industry as burnt and commands a lower market price. 3'

A considerable amount of the I precipitated stringy casein which is allowed to remain in the acidulated whey tank is redissolved by the acid, since casein is an amphoteric compound subject This loss is recognized by the industry, and it is the aim. of the'operators to maintain a hydrogen ion concentration as near as possible to the iso-electric point of casein, namely in the region pH 4.2 to pH 4.6. In the conventional process it is difficult to maintain a uniform hydrogen ion control throughout the reacting zone. For this reason various means have been introduced to obtain a further and more uniform distribution of both acid and milk inthe reacting zone, in order that the casein produced will not be subjected to the excess acid for a long time.

A's mentioned above, the casein curd after precipitation and washing is pressed in order to remove the excess of Whey and water. During the pressing operation the agglutinated masses of casein and are compacted and will retain approximately 60-65% of water. The pressed, cakes are'then passed through a conventional type of a shredder which disintegrates the cake into small size sections suitable for spreading upon the drying frames. A properly processed casein curd should be grainy andshould upon shredding retain its graininess. This allows for a uniform l 3 v provide an improved apparatus for precipitating The slimy, stringy agglutinated masses of,

mist, so that the casein is precipitated in discrete' particles which may be readily washed free of impurities.

Another object of the invention is to provide an apparatus, for producing casein which is eco nomical; and simple in operation. I ,Ajfurther object ofthe invention-.is' to produce a pure casein having a wider range of industrial application due to its purity; also to improve casein and its manufacture in other respects hereinafter specified and claimed.

Reference is to be had to the accompanying drawing forming a part of this specification, in

tom 7 for conducting liquid skim milk at a tem- .perature of Sill-110 F. into the reaction chamber 5. If desirable the milk can be diluted with water.

A compressed air inlet pipe ll] also leads through the bottom 7, being provided on its inner end" with a restricted nozzle H which aspirates the milk from an angular fitting l2 on the end of pipe 9, and delivers the milk as an atomized spray or mist into the chamber 5. A pipe it leads through the opposite side of the chamber bottom i and delivers a precipitating gas 01' vapor, such as hydrochloric acid gaasulfur dioxide or thelike, into the chamber 5 to mix with the milk spray and precipitate the casein. If desirable inlet l3 .can be replaced with a conventional atomizing device, for instance as-shown by pipes I l and 12, wherein a liquid precipitating agent in a very fine mist form can be employed. The mixture of casein and whey discharges from the outlet -port 8 onto a filter belt it which serves to separate the casein from the whey. In order to wash down accumulated casein from the walls of chamber 5 as it may be deposited, a pipe [49.

leads through the top of the dome 6, and is provided at its lower end with a suitable spray nozzle i5. The nozzle i5 is preferably. of the Whirl-. ing spray type which directs a small quantity of wash water at a high velocity against the inside of dome 6 and chamber 5. Compressed air may be also passed through the nozzle l5 in orderto finely atomize the wash water, and increase its velocity. Suitable valves l5, l7, l8 and I9 areprovided on the pipes 9, i ii, iii and Ma respectively in order to control the flow of the various rea e A catch pan 20 is provided below the upper reach of filter belt 54 to catch the whey passing through said belt. A spray pipe Zlis positioned" above the belt Hi and pan 20, being provided at its lower end with a spray nozzle 22' so as to direct wash water onto the casein supported on belt 14,

and wash soluble impurities from said casein. 1 A

valve 23 is provided on pipe 2! to control the-flow.

of wash water. Pipes 2% are connected to the bottom of pan ill; to conduct the combined whey and,

wash water to a discharge point for further processing. Ir" desired, a partition 25 may beprovided in the pan fill to keep separate the whey and-wash water from pipe 2 l. After a suitable draining pe;

riod, pressure rolls 26 and 211, may be pressedagainst the two faces of belt l i,'by a spring 28 connecting rock arms 29 and 36 on. which the rollers 26 and 2? respectively are rotatably mounted. The lower roll 26 may have its shell perforated in order toallow the water pressed from the casein to be more easily removed therefrom.

If the casein is to be dried, the belt M passes from pressure rollers 28 and 21 into an elongated drying chamber 32 which is provided-with "casein into a receptacle 31. In some cases it may not be necessary to dry the casein after it leaves the pressure rol1ers26 and 21, as the moist curd maybe used'directly. Thus this moist curd may be dissolved in a suitable alkaline solution, such as one of borax, and then mixed with other devsired'ingredients for the manufacture of paint and adhesive compositions.

The flow of milk and precipitating reagent is "preferably controlled so that the resulting whey is faintly acid, having a pH valueof about 4.6. Under these conditions, the casein. produced will have an ash content of about 1.5% which is substantially lower than other caseins now being commercially produced. My casein has a viscosity of about 92 seconds when tested according to standard methods. -One outstanding advantage of myprocess is that the precipitated casein is in the form of small, discrete particles inherent to the vaporous type of precipitation, so that the washingv is unusually eifective in removing impurities. .Under varied conditions the ash content of ,the casein may be reduced still lower than 1.5%. It should be understood that my process may also be applied to solutions of vegetable proteins, such as those derived from soya beans, corn, etc. Various precipitating reagents may be used, such as hydrogen chloride gas, sulfur dioxide, volatile organic acids, etc. Chlorine, bromine or other bleaching and modifying agents may be injected into the chamber 5 so that the casein will be'bleached and preserved from decomposition, or its properties actually modified by direct chemical union of the agent with the casein. The milk may be atomized by pressure spraying without the use of compressed air.

This application is a divisional application carved from my copending application Ser. No. 139,767, filed April 29, 1937.

I would state in conclusion, that while the examples; described constitute practical embodiments of my invention, I do not wish to limit myself precisely to these details, since maniiestly the same maybe considerably varied without'departing from the spirit of the invention as defined'in theappended claims.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. In an apparatus for preparing casein, a

reaction chamber of relatively large volume, said chamber being provided with an unrestricted bottom outlet, means for directing atomized casein solution and. vaporous precipitating agent into the centrahportion ofsaid chamber above said outletfand a water spray positioned at the top of saidchamber and arranged to continuously wash the sides of said chamber and to discharge precipitated casein from 'said chamber.

2. In an apparatus for preparing casein, a reaction-chamber of relatively large volume, said chamber being provided with an unrestricted bottom outlet, means for directing atomized case in solution and vaporous precipitating agent upwardlyinto said chamber above'said outlet, and

a whirling Water spray positioned at the top of said chamber.

3. In an apparatus for preparing precipitated casein from skim milk, a reaction chamber of,

relatively large Volume, said chamber being provided with an unrestricted bottom discharge opening, means for introducing skim milk and atomizing air into the center of said chamber and in an upward direction, means for directing a vaporous precipitating agent upwardly and can traily into said chamber adjacent said opening, and a water spray positioned at the top of said chamber and arranged to continuously wash the sides of said chamber to discharge precipitated casein from said opening.

ELMER B. OBERG. 

